The deliberate attack on the farm, near Ardara in south-west Donegal, weeks before thousands of the animals were due to be culled for the fur industry, has been blamed by the owners of the mink on "animal liberation terrorists".

Yesterday, wildlife conservation rangers who are monitoring the recovery operation, confirmed that many of the thousands of animals that were released from their cages had since been returned to the farm.

"Our information is that a sizeable number has now been trapped and recaptured. We expect that the number that will remain at large ultimately will be less than 100," said Dave Duggan, deputy regional manager with the National Parks and Wildlife Service.

He said that over 40 people were setting traps and catching escaped mink in the vicinity of the isolated farm while members of a local gun club were trapping or shooting them.

"Others have been hit by cars or are simply perishing because they are unused to the wild," he said.

The wildlife officer said that the biggest threat to the farmed mink that remained at large in the wild would come from other mink and humans.

"The fact is that a certain number of these mink will naturalise in the wild. American mink have been part of the national fauna since the 1950s and they are quite territorial.

"These farmed animals are at a disadvantage trying to compete for food. They are like innocents abroad," he said.